In recent years, as a classifier learning method, a method has been proposed in which the person gives an attribute corresponding to each learning sample to the learning sample in learning data in advance and a two-class classifier, which is a classification metric for classifying the given attribute, is learned. For example, when the learning sample is the image of the face of the person, the attribute given to the learning sample includes gender and the like.
In such learning method, various kinds of attributes are given to each learning sample in advance and the two-class classifier for each of the given attributes is learned. A plurality of learned two-class classifiers is used for recognizing an object by using the output value of each two-class classifier as the feature value of the object.
However, in the related art, the person needs to give the attribute to the learning sample, which results in an increase in cost.